Landing light for airplanes



Oct. 15, 935.- J. P. GATY 2,017,692

LANDING LIGHT Foix AIRPLANES Filed March 9, 1955 INVENTR Jaim Zaly Patented Oct. l5, .1935

LANDING LIGHT Fon AmrLANEs Johnr. caty, Woodside, N. Y., signor tor'airchild Aerial Camera Corporation, Woodside, N. Y., a corporation of New York Application March 9, 1935, Serial No. 10,180

sclaims.- (Cl. 334-43).

This invention relates in general to landing lights for aircraft. It is fully appreclatedthat airplanes are provided With ordinary altimeters and the like for 6 indicating the altitude of the airplane. In night iiying however this altitude indication is nsuflicient for landing. purposes. In other words a pilot would not want to rely entirely upon such an altitude indication alone while landing. The ordi- 10 -nary xed landing lights' for projecting light beams forwardly of the airplane does not give a very exact indication as to the altitude of the airplane during its lan'ding glide: I am aware of the fact that it had been proposed to project light l5 beams substantially vertically from the underside of the airplane .for visual indication of the` alti'- tude of the airplane. This type of visual indication Ais however unsatisfactory in that an observation ofsuch light beams would necessarily distract L-the pilots attention from the point on the terrain towards which the airplane is headed.

In providing adequate landing lights -for airplanes, it is important to provide the pilot with a v clear view of the terrain and the objects ahead 261fduring the different attitudes that the airplane takes while on the ground with respect to its transverse axis and the different attitudes that the airplane may take while in iiight with respect' to its transverse and longitudinal axes. The usual fixed landing lights-'are inadequate as they merely extend straight ahead either along the longitudinal axis of the airplane or at a fixed angle thereto. Hence they are adequate only' for a normal straight landing glide. l

Such lighting systems are inadequate in the event that the landing-operation includes such an airplane vmaneuver as' a slip or a turn as the lights would under such conditions not be trained upon the ground ahead where the landing is to 40 5taire place. It would therefore be necessary-to makev these lights adjustable so that the pilot could shift them while he is landing if the landing maneuver included a slip or a turn. Now the pilot is -already ov'erburdened with instruments and .45 controls ofvarious kinds and itis therefore one of the objects of -this invention to provide an adequate lighting system for all conditions without the necessity of manual adjustment or control of the lights.

'? One of the main objects of my invention is to provide such a stationary landing light system which by predetermined arrangement thereof will aord a visual means readily discernable ahead on the ground during the gliding maneuver enable the pilot to orientate himself as to his altitude at the time at which he'should place the airplane in the proper attitude for landing.

One of the objects of my invention is to provide a stationary lighting system that will aiord.

an adequate illuminated area directly ahead of 5 the airplane while making a straight approach for landing.

Anotherobject is to provide a stationary lighting system that will afford an adequate illumination of obstacles that may be directly in the path 10 of the wheels while the airplane l.is in motion on the ground. 1

A further object is to provide a stationary lighting system that will afford an adequate illuminaltion of that point on theterrain toward which the l5 airplane is turning or slipping as distinguished from' the direction in winch the airplane is pointing. I

With the foregoing and other objects in view, the invention consists in the combination of parts 20 and -in the details of construction hereinafter set forth in the following'specication, certain em- .bodimentsthereof being illustrated in the accompanying drawing, in which:

Figurey 1 is a diagrammatical view in top plan 28` of an airplane'showing the position of the wing lamps and their reflectors and alsmshowing dia- .gr'ammatically the light beams emanating there- Afrom and the projected illuminated areas from Figure 2 is a diagrammatical view in side elevation of the airplane showing the same disposed at a normal gliding angle with respect to the terrain, showing the light' beam emanating from one of the lamps and also diagrammatically illustrating 85 -diiierent altitudes at which certain maneuvers of the airplane should takeplacefor landing pur- POSeSi Figure 3 is a view in side elevation of the alrplane showing the same in dotted lines disposed 40 substantially horizontally just prior to the position shown in full lines which should be adopted just prior to the time the airplane .comes in contact with the ground and also showing the projected light beams from one of the lamps inthe 46 twoy mentioned positions;

Figure'4 is a 4view in side elevation of the airplane showing the same and the light beam projected by one of the lamps when the airplane is at rest 'on the ground or in a position fortaxling 50 y thereon.

Referring more particularly to the drawing I vhave shown as a. preferred embodiment an airplane generally indicated -at 5 provided with a f,

conventional wing' 6to whichI attach lamps and. 5l

their reectors as indicated at I, 2, 3 and 4. I prefer to dispose the inner lamps 2 and 3 so that their projected light beams are substantially parallel to the longitudinal axis of the airplane. The lamps I, 2, 3 and 4 are preferably disposed at a fixed angle with respect to the wing so as to project light beams downwardly at a predetermined angle. The lamps I and 4 are also disposed at such an angle inwardly that the light beam ID of lamp I will cross light beam 3D of lamp 3, and light beam 4D of lamp 4' will cross light beam 2D of lamp 2. The angular disposition of the lamps with respect to the wing depends upon the gliding characteristics of the particular aircraft on which the lights are to be installed. They are so positioned that the light beams cross at the points at which they strike the terrain and at a predetermined distance ahead of the aircraft when the same is proceeding at a normal gliding angle of attack and is at a given altitude above the terrain. For landing purposes the airplane should be adjusted about its transverse axis so as to assume a normal gliding angle as generally indicated in Figure 2. As the airplane assumes this normal gliding angle at an altitude C, indicated by the line G above the terrain A, the light beam ID of lamp I illuminates an area IC and the light beam 4D of lamp 4 simultaneously illuminates the area 4C. Like- Wise the light beams 2D and 3D of lamps 2 and 3 are simultaneously illuminating respectively the areas2C and 3C so that these illuminated areas IC, 2C, 3C and 4C are separate and distinct from each other as indicated in Figure l. This, of course, is due to and dependent upon the spacing and the angular disposition of the lights and the height of the airplane above the terrain.

When the airplane during its descent reaches a given altitude B measurable by the line F from the terrain A, the light beam ID intersects light beam 3D and beam 4D intersects beam 2D at the points at which they strike the terrain. As a. result the illuminated areas IB and 3B coincide and the illuminated areas 2B and 4B also coincide so that the two resulting illuminated areas are spaced laterally on the terrain in the relative positions shown in Figure 1. Since the characteristic gliding angles for different airplanes are known, the angular disposition of the lamps I, 2, 3 and 4 may be mathematicaily calculated so that the coincidence of the crossed light beams will be obtained at a known distance ahead of the aircraft while the aircraft is at a known height. While making an approach for a landing the pilot may be fully assured that as long as the four lighted areas IC, 2C, 3C and 4C are distinct and separate he has not come sufficiently close to the ground for leveling olf purposes. As soon as he sees the four illuminated areas merge into two areas he is visually warned as to his altitude and of the fact that he vshould level o the airplane for landing.

Failure to act upon this warning within a short space of time, and a continuance of the glide at an angle indicated in Figure 2 to an altitude H, measurable by the line E from the terrain A,'Wi1l result in the provision of three separate illumin'ated areas, namely the separate areas 2A and 3A and the coinciding areas IA and 4A. 'I'his distinctive pattern of illuminated areas takes place upon this further decrease of altitude as the light beams ID 'and 4D 'intersect each other at the point where they strike the terrain and no longer intersect light beams 2D and 3D where the latter beams strike the terrain. The lamps 2 and 3, not being angularly disposed with respect to each other or to the longitudinal axis of the airplane, their light beams 2D and 3D never intersect each other. When the pattern assumes this latter mentioned form, namely the three 5 resulting lighted areas 2A and 3A and the merged area IA and 4A, it will constitute a last warning to the pilot that he must act quickly in leveling 01T the airplane to avoid a crash which would naturally result by continuance of the glide until 10 the airplane hit the terrain.

The two stages of leveling oil after changing from the glide indicated in Figure 2 are shown in Figure 3. Here in dotted lines is shown the airplane 5' with its wings 6 and one of 'the lamps 15 at I' in such position" that the angle of attack is substantially zero. Subsequent to bringing the airplane into this position it should be adjusted about its transverse axis so vas to present a positive angle of attack, thus placing the air- 20 plane in landing position. The airplane is shown in Figure 4 as being in its proper position when either at rest or for taxiing on the ground.

This lighting system, besides providing a very deiinite means of orientation for the pilot as to 25 his altitude, very denitely constitutes a visual indicating device for gauging his maneuvers during the landing operation. The.arrangement of lamps is also made for the purpose of providing adequate illumination whether the airplane is in'30 a straight glide for landing, or coming in to landing during a turn or slip, there always being provided sufficient illumination of the terrain towards which the airplane may be approaching. In taxiing position the light beams 2D and'35 3D are preferably projected diagonally downwardly but otherwise straight ahead in parallelism with each other andthe longitudinal axis of the airplane. As a further precaution for adequate lighting purposes I prefer to arrange these twol lamps 2 and 3 so that they will be immediately above the landing wheels themselves. 'This is for the purpose of sufliciently illuminating the terrain directly ahead of the landing wheels so as to illuminate any obstacles in the way thereof. 45 .y The light beams ID and 4D after they cross each other afford an expansion of the lighted area with regard to the longitudinal axis of the airplane while the airplane is being taxied as well as while it is being landed. 50

One of the great difficulties in heretofore used landing light systems has been the lack of provision of lights that would illuminate the ground towards which the airplane is'actually approaching when it was in a turn or a slip or any other 55 attitude than a straight forward glide. For instance, in a turn or a slip, the pilot has been unable to see the ground toward which .the end of the relatively lower wing of the airplane'is approaching. By means of my preferred light- 60 ing system should the airplane be rocked about its longitudinal axis so that one wing is relatively higher'than the other as would be the case in a turn or a slip, that lamp adjacent the upper' wing by reason of' its angular disposition il- 65- luminates an areav on the terrain toward which the airplane is actually approaching. For instance, assume in the illustration in Figure l, the airplane to be rocked to the right about its longitudinal axis to assume a vertical or lesser 70 I degree of bank for a turn or slip. The light d.' in this case being adjacent. the upper wing, projects a beam 4D downwardly so as to illuminatean area 4C which in this case is in the direction towards which the airplane is actually approach- 75 luminate an area IC toward which the opposite wing would actually be yapproaching during this landing operation. f Y

It will 'thus be seen that I- haveprovided a lighting system for furnishing adequate illumina-- tion of the ground for taxiingl andtaking-oil purposes and also for landing purposes', whether the landing maneuver consists solely of a straight glide or includes a turn or slip. Itvwlll also be seenthat I have provided an adequate visual Warning system for night landing, lthe warning to consist of an initial and final one for the purpose of allowing the pilot to properly land the airplane solely by observation of either or both.

l. In combination with44 an Iairplane, a landing light system comprising an inner pair of lamps and an outer pair; of lamps on said airplane, said inner pair of lamps being so disposed with relation to each other and to said airplane as to projectbea'ms of light extending downwardly with respect to the :longitudinal axis of said airplane and substantially parallel to each other in a direction forward oi.l said airplane,

said outer pair of ,lamps being so disposed `with relation to each other and to said airplane'as to project light beams downwardlyvand inward- I and at a known altitude above the landing surly so as to intersect each other at a predetermined distance forwardly of said airplane and toalso intersect said parallel light beams a relatively further distance forwardly of said air-` plane bringing about illuminated areas on the' landing surface during a predeterminedy gliding angle of said airplane which willvbe separate. partly coincidental or coincidental as the length of the beams vary between the illuminated areas and the light source during said glide and the subsequent change ln'altitude.

2. In combination with an airplane, a landing light system including a pair of laterally spaced lamps on said airplane for. 4projecting light beams forwardly of said airplane, and downwardly with rrespect to the longitudinal axis of said airplane and substantially parallel tojeach other, a pair offlamps thereon respectively arranged on voppositelsides of said first named pair of lamps and so angularlyv disposed downwardly and inwardly'as' to project light beams thatconvergeto intersect each other at a predetermined point ahead of said airplane and then diverge so as to each intersect one of the light beams of said first named pair 'of lamps at points in-a straight line a predetermined distance still further ahead of saidairplane, Y

3. In combinationwith an. lane,I a landing light system including a pair of laterally spaced lamps on said airplane for projecting light beams forwardly of said airplane, and

downwardly withres'pect to the longitudinal axis of. said airplane and substantially parallel to each other, a second pair of` .lamps thereon re.

ys'pectively arranged `'on opposite sides of-said first named pair of lamps and -so angularly disposed downwardly and inwardly as to project 'said airplane and by the merging of said il-l y during said glide.

at e predetermined peint ahead of seid airplane' and then diverge so as to each intersect one 0f the light beams of said first named pair of lamps at points in a straight line a predetermined dis-v tance still further ahead of said airplane, the 5 relativeangles of disposition of said lamps being so predetermined with relation to thel gliding angle of the airplane as to illuminate areas on the landing surface during the normal Aglide of luminated areas atv the pointsl at which-certain light beams simultaneously strike the landing surface and intersect each other, constituting a visual indication of the altitude of the airplane f l5 4. In combination with an airplane, apair of lamps thereon so positioned as to project light beams extending forwardly and substantially parallel to each other but downwardly with rei spect to the longitudinal axis of said airplane, a 20 second pair cf lampsso positionedas to project light beams downwardlyand forwardly and in"- -wardly so as to intersect each other land the beams of said first pair oflamps.

'5. In combination with an airplane, a pair Vof I' lampsthereon so positioned as to project light beams 'extending forwardly and, substantially ject light beams downwardly a'nd forwardly and inwardly with respect to said airplane and said. longitudinal axis of said airplane so as to intersect. each other and the beams of said first pair l of lamps, all of said lamps being positioned at g5 predetermined angles with respect to the wings of said airplane so that during -a normal glide face the beams of `one pair oLlamps will eachintersect one beamof the other pair of lamps at 4 the instant the beamsstrike the landing surface so'that the illuminated areas on the landing sur- .face resulting from the four lbeams will merge into two illuminated areas, providing a visual indication of warning to the pilot to level off'the airplanefor landing.

a .second 4pair of lamps on said airplane so positioned as to project light beams downwardly and forwardly and inwardly with respect to said airplane and said longitudinal-axlsof said airplane so as to yintersect each other and the beams of said first -pair of lamps, all of said lamps being positioned at predetermined angles with respect Y to the wings. of said airplane so that during laico normal glide and at a knownaltitude above the terrain the beamsof one pair of -lamps willfeach i'ntersectone beam 'of the other pair of lamps at the landing surface so that the illuminatedareas an initial warningto the pilot to level oil' the 'f airplane for landing, andupon a further decrease in altitude during said glide the beams from said f second pair of lamps intersect each other {to 'I0V merge their two illuminated areas-into one at-the landing surface which in addition to' the. two illuminated areas of the-beams of said `rst pair Yoflamps on said surface provided three illumilight beams that converge to intersect each other f nated areas `to constitute' a indication of 'la l said known altitude and an initial s extending forwardly `and substantially 5o a known altitude above the landing suriaceand a second and inal warning to the pilot to level oil the airplane for landing.

7. In combination with an airplane, a landing r5 light system thereon comprising a plurality of pairs of lamps on said airplane, one pair being adapted to project spaced light beams extending forwardly and downwardly with respect to the longitudinal axis of said airplane and substanlm tialiy parallel to each other, a second pair of lamps being so angularly disposed with respect to each other and to the longitudinal axis of said airplane as to project light beams downwardly and forwardly and inwardly with respect to said 15 airplane and said longitudinal axis of said airplane as to intersect each other and the beams o! said ilrst pair of lamps, said points of intersection of said beams being deter-minable with respect to a predetermined altitude of said air- 20.Dlane in a predetermined glide so as to constitute, by means of the observed coincidences of projected lighted areas on the landing surface, a

separate initial indication and i'lnal indicationof said altitude during said glide.

8. In -combination with an airplane, a landing 4 mimosa f r' light system thereon comprising an inner pair of lamps and an outer pair o! lamps on said airr plane, said inner pair of lamps being so disposed with relation to each other and to said airplane as' to project beams of light extending down- 4 wardly with respect to'the longitudinal axis of said airplane and substantially parallel to each f other in a direction forward of' saidy airplane,

said outer pair of'lamps being-so disposed .withrelation to each other and to saidairplane asto lo project light beams downwardly and inwardly so as to intersect each other at a predetermined distance forwardly of said airplane and to also intersect said parallel light beams a relatively further distance forwardly o1' said airplane bringing 15 about illuminated areas on the terrain which simultaneously merge into vtwo illuminated areas when said` airplane, during a normal glide at a known altitude above the landing surface and with the transverse axis of said airplane in a 20 horizontal plane so as to provide a visual indication of said known altitude and, the lateral position of said 'airplane during said glide.

JOHN P. GATY. 

